Danny was just tired about the way things were going. His mum came to school and talked on and on about Rick Jackson. It seemed that she would never stop talking. “Somebody’s got to stop that boy!” she was shouting. “Rick’s troubling everybody in the neighborhood. And he loves to pick on little boys like Danny.”
   Mrs. Green, Danny’s teacher, was concerned a lot. “I didn’t know that Danny was being picked on,” she said. “He’s never said anything about this to me!” Mrs. Green looked at Danny. “How long had this been going on?” she asked. Danny could only shake his head and look at the floor. He knew if he said a word about this, he would have trouble at school.
   Danny hadn’t said anything about the problem because he wanted to do things with the boys in the neighborhood. After all, most of them were nice to him. He hated to leave the gang just because of Rick. Maybe the time had come to find new friends. He felt it hard to make up his mind.

①三块小石头放在盛有少许清水的容器内形成三个小岛，

小岛间用两根等长的小木条连接起来，这样蚂蚁只能通过由

小木条搭成的“桥”从一个小岛到达其它的小岛。

②先将饥饿的蚂蚁放在B岛上，食物放在C岛上，A岛什么都不放，发现蚂蚁经过几次寻找后，在C岛上找到食物。

③小组成员将连接BC岛的“桥”和AB岛的对换，结果发现蚂蚁并没有爬向有食物的C岛，而直接爬向A岛。

化学用语是学习化学的重要工具，按要求用适当的化学用语填空：

①氖气____；②2个二氧化硫分子____；③地壳中含量最多的金属元素____；④核电荷数为14的元素____；⑤ 表示____的结构示意图；⑥氧化镁中镁元素的化合价为+2价____ ．